Process of treating water



Aug. 20, 1963 D. ROSE 3,101,316

PROCESS OF TREATING WATER Filed Sept. 12, 1960 v 00mm R055' BY )l ATTORNEYS' .dlld PRCESS F MATEN@ WATER l y Donald Rose, Dayton, Ghia, assigner et auahalfto Ronald l). Baker, Dayton, Ohio Filed Sept. 12, 196), SenNo. 55,239 .6 Claims'. {CL Zilli-3S) T his invention is directed to improvements in a method of treatment of water to remove hardness, iron in solution and par-ticularly iron and turbidity in suspension.

This invention is a continuation-in-part of my copending applications Serial No. 7 07,267, tiled January 6, 1958,

now U.S. Patent 3,044,626, issued July 17, l962; Serial No. 785,237, led January 6,y 1959, now US. Patent 3,014,497, issued December `26, 1961; and Serial No. 21,720, filed April 12, 1960, now U.S.V Patent 3,080,975, issued March 12, y1963. y l

1t is an object of the invention to ltreat water to remove hardness and turbidity including iron in solution and iron in suspension.

Another object of the inventi down ilow fast rinse of the bed to remove regenerate solution pockets and turbidity and iron deposited in the mineral bed Where iron bearing waters are treated.

Still further objects and the entire scope of applicabil-v ity of the present invention will become apparent from the detailed description given hereinafter. It should be understood, however, that the detailed description and specific example is given by way of illustration only and, while indicating a preferred embodiment of the invention, is not given by way of limitation, since Various changes and modiiicationswithin the spirit and scope of the invention will become apparent to'those skilled in the art from this detailed description.

' F or a more completely understanding of the nature and scope of the invention refernce may be had to the drawing in which FIG. 1 is a diagram illustrating the water treatment cycle of water through a mineral'bed;

FIG. 2 is a similar diagrammatic showing but showing up flow backwashing of the mineral bed in reconditioning the same;

PIG. 3 is a showing of the introduction of regenerate solution to the mineral bed from regenerate solution storage;

FIG. 4 is a diagrammatic showing of the slow rinse v downilow of the mineral bed; and

FIG. 5 is a diagrammatic showing of the fast rinse and regenerate Water replacement.

Throughout the description of the diagrams of flow, like reference numbers and characters refer to similar parts or elements.

Synthetic resin minerals have been used for some time in the treatment of Water to remove hardness and iron in solution. The mineral bed will also iilterout turbidity and iron that may be in suspension. Applicant has found that to obtain the most eflicient utilization of the minerals used for the minenal bed certain procedures must be carried out in the use of the mineral bed and its rehabilitation. It is known that the minerals in the water causing the so called hardness may be treated and certain iron traces in solution can likewise be removed by the reaction in the mineral bed but turbidity and iron in suspension in on is to make maximum `use of an ion exchange mineral in the treatment of water 3, l d Mild Patented Aug.' 20, 1963 ice the Waters being treated has not heretofore been properly reduced and elimnated to provide an iron and turbidity free Water.

The invention is thus directed to a solution of this problem to obtain the maximum usefulness of a given mineral bed and particularly to also remove turbidity and iron in suspension where the waters treated are iron bearing waters. j

'It is assumed that the mineral bed when new has the characteristics and capacity to remove the mineral hardnes and iron in'solution and suspension. The invention is directed to the proper regeneration and handling of 'this bed to restore its original or substantial original condition.' lt is recognized that theiron slippage through the mineral bed will notincreasefmuch more than to 30%'. For example, if the slippage through anew condition mineral is 1/2 part per million it will'not increase to over 2%; to 3710 per million. o

Removal of iron by the cation exchange process is similar to and simultaneous with the removal of calcium and magnesium. The-'removal of turbidity and insoluble iron that is trapped in the mineral bed and not fully backwashed out is accomplished by this process if treatment of the mineral bed in its rehabilitation is followed as will bedescribed according to the invention.

v Various types of minerals may be utilized. The cation exchange materialmay be green sa-nd, zeolite which term is applied to insoluble, solid materials which have the property of exchanging various ions with which they come in contact and such zeolite materials include synthetic resin materials. Various regenerate materials maybe utilized to rehabilitate the spent mineral bed. The sodium zeolite softening process is here used and this is also referred to as cation exchange ony the sodium cycle. Sodium chloride may be used as the' regenerate material.

Reference to the drawing sliows'in FIG. la softener tank S having a mineral bed M on a layer of quartz iilter sand G.' The softener tanlt has an inletconduit 10 at the top and an outlet conduit l1 at the bottom. The inlet l0 and outlet l1 are connected with an automaticalflow in the system during m200 as shown in my referred to copending applications which ds `fully operated by two solenoid actuators. The flow in the conditioning or service cycle 1 is with the hard Waterowing down lthrough the mineral bed M.

In FIG. 2 there is illustrated the start of the reconditioning, cycle No. 2, an up flow backwash whose rate is such as will be `described fora typical Vsynthetic mineral such as to afford about a 40 to 50% expansion. This up ow backwash loosens the minenal bed and removes some `of the filtered'` or trapped turbidity and in iron bear-ing waters iron in solution that has been physically trapped by the @mineral bed. Baclcwash lalso stnatifies the mineral bed. wherein the smaller minerals tend to stnatify out on top. 'i'ihis backwash is at a recommended rate usually specified by the min-eral manufacturer to accomplish loosening of the mineral 'without washing it away with the entrapped material Ibeing backwashed `from the bed. The backwash is led to a drain as a point of disposal.

Referring now to FIG. 3 there is in addition shown diagrammatioally a typical brine tank or regenerate solution supply. Along with the @brine or regeneration solution supply line there i-s an air check AC and a ow control valve FC whereby a given quantity of brine will flow in step with :a pressure supply range variation. It is essential to remove air las much las possible. It is to be noted that the regenerate solution is introduced at 12 just above the mineral bed M and below Vthe head of free board water F and constitutes cycle No. 3.

Following the regenerate solution introduction there is a slow rinse down through the mineral bed yand in the illustration in FlG. 4, cycle No. 4, the slow rinse water is introduced just above the mineral `bed M through the same conduit l2 through which the regenerate solution was introduced.

In FIG. 5 there is illustrated cycle 5 which is the very important fast rinse according to the invention. The fast rinse is at a rate tbout twice that of the backwash rate lfor la synthetic resin mineral. It will be in quantity about 2.0 gallons per cubic feet of mineral in the bed or in terms of softener tanlr capacityk it will -be about two times the softener tank capacity with mineral installed. These rates and amounts of bachwash will for the majority of cases remove any regenerate solution pockets left in the mineral bed, remove any left turbidity and iron in suspension that 4may have been 'left in the mineral bed and will repack the mineral bed. Thus, when the No. 1 cycle of service or softening takes place there will be no carry over of regenerate solution and turbidity and in the case of iron bearing waters there will `be no tnace of iron insuspension carried over which is so detrimental.

The softenerbed as illustrated is of a depth of about 30 inches.

Y Erample of a Mineral Used Sodium Cycle Operation Type-(lation exchange resin-chemicallytermed a mono-functional, sulfonated, copolymer of styrene and divinylbenzene.

Manufacturer- Dow Chemical Company Tradename-Nalcite HCR-W Size, color and shape The resin material consists of water white spheroidal particles with sphericity greater than 95%. The particle size distribution is usually 96% smaller than -16 mesh and larger than 40 mesh.

Flow rate-dd() gal. per minute per square foot o bed tarea. l

Backwash--A backwash rate of 8 gal. per sq. 4foot per minute of mineral bed at 78 F. of wash water will give ialbout Ia 50% expansion of the bed. To maintain a specific expansion the ilow should be changed V0.75% for each degree F. wherein there is an increased iiow rate with increased temperature of water. U

In carrying out the fast rinse, cycle No. 5, according to the invention the following minimums should govern:

Total gallons of fast rinse Water is based on the number of cubic feet of mineral in bed and with la :mineral of the type set out in the example, a synthetic resin mineral, there should be 2O gal. of ast rinse water per cu. tft. .of mineral bed. In terms of softener tank capacity with mineral installed there should be an amount equal to two times tank capacity or greater. The ow rate in gallons per minute is equivalent to at least twice the backwash rate to give a 40% to 50% expansion of the mineral bed.

I claim as my invention:

1. The process of ion exchange using an ion exchange high capacity resin mineral bed with -a freeboard head or `water thereabove with an inlet above the freeboard and an outlet below the mineral bed which comprises the steps of (a) passing water through said inlet and freeboard spaced and down through said bed during the service phase yand withdrawing the treated water after treatment thereof `from said outlet yto a point of use; recondruoning said bed by (b) backwashing upwardly by introducing `vwater at the outlet below the bed and withdrawing same through said inlet to a point of disposal at a rate so' as to expand the mineral bed yabout forty percenturn without removal of mineral through said inlet, (c) introduc- 'fi ing a regenerate solution above said bed and below said freeboard `space and withdrawing the resultant regenerate solution from said outlet below the bed to a point of disposal, (d) slow rinsing said bed by introducing water above said bed and below said freeboard and (e) fast rinsing by introducing water at said inlet and withdrawing from said outlet below the bed to a point of disp-osalat a rate about twice the backwash rate of ow whereby tol remove regenerate solution pockets left in the mineral and freeboard space and to remove any turbidity and iron deposits and to repack said mineral bed whereupon a subsequent service phase will provide conditioned water without traces of regenerate solution and iron deposit in case of ir-on bearing waters being treated.

2. The process of ion exchange using a cation exchange high capacity resin mineral bed with -a freeboard head vof water thereabove with an inlet above the freeboard and an outlet below the bed'which comprises the steps of (a) passing water through said inlet and freeboard space and down through` said bed during the service phase and withdrawing the treated water after treatment thereof from said outlet to a point of use; reconditioning said bed by (b) backwashing upwardly by introducing water at the outlet below the bed and Vwithdrawing same through said inlet to a point of disposal at y'a rate so as to backwash and expand said bed by about 40% without removal ot mineral through said inlet, (c) introducing a substantially air `free sodium chloride solution Aabove said bed and withdrawing the resu-ltant solution from said outlet below the bed to a point of disposal, (d) slow rinsing said bed by introducing waterv -above said bed and (e) fast rinsing by introducing water above said bed in a minimum quantity of about 20 gallons per cubic foot of said mineral in bed andata rate about twice the backwash rate of iiow whereby to remove any sodium chloride pockets left and to nemove turbidity and iron deposits and to repack said mineral bed whereupon a subsequent service phase will provide conditioned water without traces of sodium chloride and iron deposits in case iron bearing waters are being treated.

3. In a cyclic process `for treating water in an ion exchange process using an ion exchange mineral bed, said ion exchange mineral being characterized as a mono-functional, sulfonated, copolymer of styrene and divinylbenzene with par-ticle size distribution about 96% smaller than 16 mesh and larger than 40 mesh and having said particles spheroidal to about 95 of the particles, wherein there is down ow treatment of the water through the bed, an up ow backwash :of water through the bed in an amount of approximately 8 gallons per square foot per minute of said mineral bed at a rate with backwash water v temperature of about 78 F. to give about a 50% expansion of the mineral bed and wherein the rate of backwash ilow should be changed 0.75% `for each degree F. change to maintain the approximate 50% expansion wherein there is an increased flow rate with lincreased temperature .of water, a regeneration of the bed by passing regenerate solution downwardly therethrough, a slow rinse down through the bed, the improvement yof a fast down ow water rinse through the mineral `bed at a rate about equal to twice said backwash rate of ow to remove any pockets of regenerate solution and to remove residual turbidity and residual iron deposits and to repack said mineral bed whereupon a subsequent service phase will providel conditioned water without traces of regenerate solution and iron deposits in case iron bearing waters are being treated.

4. A cyclic process for treating water according to claim 3 wherein the ion exchange mineral is cation exchange resin and wherein the regenerate is a solution of sodium chloride.

5. In a cyclic process for treating water in an ion exchange process using an ion exchange high capaci-ty resin mineral bed wherein there is (a) down ilow treatment of the water through the bed at a rate, (b) an up flow back- Wash of water through the bed so as to expand the mineral bed approximately 40 Ito 50% without removal of mineral, (c) introduction of a regenerate solution down through said bed from above the bed, (d) slow rinsing of said bed by passing water down through said bed, the improvernent of (e) fast rinsing said ion exchange mineral bed with a down oW therethnongh by a quantity of about 20 gallons `of water per cubic foot of mineral in said bed 6. A cyclic process for treating water according to claim 5 wherein the ion exchange mineral is cation exchange resin land wherein the regenerate is a solution of sodium chloride.

References Cited in the le of this patent UNITED STATES PATENTS 

1. THE PROCESS OF ION EXCHANGE USING AN ION EXCHANGE HIGH CAPACITY RESIN MINERAL BED WITH A FREEBOARD HEAD OF WATER THEREABOVE WITH AN INLET ABOVE THE FREEBOARD AND AN OU!LET BELOW THE MINERAL BED WHICH COMPRISES THE STEPS OF (A) PASSING WATER THROUGH SAID INLET AND FREEBOARD SPACED AND DOWN THROUGH SAID BED FURING THE SERVICE PHASE AND WITHDRAWING THE TREATED WATER AFTER TREATMENT THEREOF FROM SAID OUTLET TO A POINT OF USE; RECONDITIONING SAID BED BY (B) BACKWASHING UPWARDLY BY INTRODUCING WATER AT THE OUTLET BELOW THE BED AND WITHDRAWING SAME THROUGH SAID INLET TO A POINT OF DISPOSAL AT A RATE SO AS TO EXPAND THE MINERAL BED ABOUT FORTY PERCENTUM WITH OUTER REMOVAL OF MINERAL THROUGH SAID INLET, (C) INTRODUCING A REGENERATE SOLUTION ABOVE SAID BED ABD BELOW SAID FREEBOARD SPACE AND WITHDRAWING THE RESULTANT REGENERATE SOLUTION FROM SAID OUTLET BELOW THE BED TO A POINT OF DISPOSAL, (D) SLOW RINSING SAID BED BY INTRODUCING WATER ABOVE SAID BED AND BELOW SAID FREEBOARD AND (E) FAST RINSING BY INTRODUCING WATER AT SAID INLET AND WITHDRAWING FROM SAID OUTLET BELOW THE BED TO A POINT OF DISPOSAL AT A RATE ABOUT TWICE THE BACKWASH RATE OF FLOW WHEREBY TO REMOVE REGENERATE SOLUTION POCKETS LEFT IN THE MINERAL AND FREEBOARD SPACE AND TO REMOVE ANY TURBIDITY AND IORN DEPOSITS AND TO REPACK SAID MINERAL BED WHEREUPON A SUBSEQUENT SERVICE PHASE WILL PROVIDE CONDITIONED WATER WITHOUT TRACES OF REGENERATE SOLUTION AND IRON DEPOSIT IN CASE OF IRON BEARING WATERS BEING TREATED. 